Aruba, September 30, 2014 - Europe’s antitrust regulator will soon provide fuller details on why it suspects Ireland and some other low-tax countries have made special deals with multinationals like Apple that helped the companies avoid billions in taxes and created unfair advantages over other European Union member countries.

As soon as Tuesday, the antitrust regulator is expected to publish a report formally describing the scope of the investigation and why it is worth pursuing. While the case is still in its early stages, any eventual decision could force the Irish government to recoup back taxes from Apple.

Apple has said it met with the Irish government to discuss taxes and provided information about its operations so that it could pay the correct amount of taxes. The European Commission’s investigation raises the question of whether Apple and the Irish government cut a special deal in that process, allowing the company to enjoy benefits that others do not.

The report will additionally outline the case involving Luxembourg’s tax dealings with Fiat Finance and Trade, a unit of the Italian automaker Fiat. The investigation, which was initially announced in June, also involves the American multinational Starbucks and the Netherlands. That report will be released at a later date.

“This investigation shows it’s not just business as usual for the commission,” said Andrea Biondi, director of the Center for European Law at King’s College London. “It could have major repercussions outside Europe, particularly for American companies.”

Apple has long insisted that it has fulfilled its tax obligations and that it has made no special arrangements with Ireland. The Irish government has said that it has done nothing wrong and that it will contest the investigation by the regulator, the European Commission.

The antitrust case reflects the growing concerns about the way Apple and other major multinational companies have conducted their tax affairs.

Besides accusations of sweetheart tax deals, American officials have been trying to crack down on so-called tax inversions, when companies try to lower their tax bills by relocating overseas often through mergers. In the European Union, officials are trying to keep countries from competing with one another in using tax treatments as a lure to big business.